Many industries utilize advanced materials in the implementation of products and services. For example, the aerospace and automotive industries commonly use advanced materials made from composite fibers in view of its beneficial properties (e.g., high strength-to-weight ratio) over traditional materials.
However, notwithstanding the benefits, often such advanced materials are less conducive to certain applications where more traditional materials might be better suited. Accordingly, for many applications, traditional materials may be used in conjunction with advanced materials. For example, an aircraft may have a body made from composite fibers that is fastened to a frame using fasteners made from a more traditional material, such as steel.
Generally, components made from traditional materials are compatible for use with components made from advanced materials. However, in certain applications, the difference between the properties of traditional and advanced materials may introduce undesirable or unintended consequences. For example, some advanced materials, such as composite materials, have a much lower coefficient of thermal expansion than traditional materials, such as steel. When used together, the variance between the coefficients of thermal expansion of the component made from an advanced material and the component made from a traditional material may result in relative movement between the components as the components heat up and cool down.
Relative movement between components may be problematic when a component susceptible to cracks is coupled to both the moving components, particularly when the difference between the coefficients of thermal expansion is significant. As the components move relative to each other, the portion of the susceptible component coupled to one moving component tends to move with that component, while the portion of the susceptible component coupled to the other moving component tends to move with the other component. The relative movement of separate portions of the same component, when the component is susceptible to cracking, tends to result in the formation of cracks on or within the susceptible component at the boundary between moving portions. For example, in aircraft applications, cracks may form in the paint around a metal fastener that secures the composite body of an aircraft to a frame. Not only is cracking unsightly, but it can lead to more serious problems, such as structural degradation, aerodynamic flaws, and even catastrophic failure.